I am sorry to hear you experienced this issue.

We're aware that some QuickBooks Online users are currently experiencing errors when viewing or printing invoices. Our engineers are working to fix it as soon as possible.

I recommend contacting our QuickBooks support team to be added to the notification list. Just make sure to request a callback during business hours (Monday to Friday, from 6:00 AM to 6:00 PM PST, and Saturdays from 6:00 AM to 3:00 PM PST. This is to ensure we're able to address your concern on time. In case you want to talk to one of our representatives, here's how:

1. Go to the Help menu.
2. Choose Contact Us.
3. Enter your specific concern in the What can we help you with? box.
4. Click Let's talk.
5. Select Get a callback. 
6. Enter your contact details.
7. Hit Confirm my call.

I've attached a screenshot below for your reference.

We’ll share updates as soon as we learn more. You may also check for updates on your end from time to time through this link: https://status.quickbooks.intuit.com/.

We appreciate your patience and understanding on this matter. Please know that we will keep you updated here in the Community.